Process for treating sewage or similar material



.Se t. 17,-1935. H. J. HARTLEY 2,015,052

PROCESS FOR TREATING SEWAGE OR SIMILAR MATERIAL Filed. Aug 17, 1934 AirINVENTOR 6 x I 6 BY l v ATTORNEYJ Patented Sept. 17, 1935 PATENT OFFICEPROCESS FOR TREATING SEWAGE OR SIIVIILAR. MATERIAL Henry J. Hartley,Hastings upon Hudson, N. Y., assignor to Nichols Engineering andResearchCorporation, New York, N. Y., a corporation of DelawareApplication-August 17, 1934, Serial No. 740,250

Russet!) 2 Claims. (01. 110-15) after passage through the combustionzone thereof to thereby greatly decrease'or substantially eliminate thenoxious or objectionable odors in said gaseous products 'of combustion.

Various other objects, advantages and characteristics of my inventionwill become apparent from the following description.

My invention. resides in the process, process steps, system, andfeatures of the character hereinafter described and claimed.

For an understanding of my invention'and for an illustration of one ofthe forms my apparatus may take, for carrying out the invention, reference is to be had to the accompanying drawing, in which:

The figure is a vertical sectional view, partly in elevation, of afurnace arrangement as constructed and arranged in accordance with myinvention. I

As shown on the drawing, F represents any suitable furnace or combustionchamber such, for example, as a multiple'hearth furnace of theHerreshoff type. As is well understood, a furnace of this charactercomprises a plurality ofsuperposed hearths surrounded and supported bythe usual furnace wall structure. As illustrated, the hearth arrangementis such that a plurality of hearths I and 2 are .provided, a hearth 2being disposed between each pair of hearths I, each hearth I beingprovided with a central opening la, each hearth 2 being provided withone or more outer openings 2a, and all of the hearths being secured inand supported by the furnace wall structure 3.

Extending axially through the center of the wall structure 3 is asuitably journalled, vertical rotatable shaft 4 which may be providedwith radially extending rabblearms 5 utilizable for rabbling thematerial over each of the hearths in succession down through thefurnace. As disclosed in Herreshofi U.-S. Letters Patent No. 976.175,November 22, 1910, the central shaft 4 and the rabble arms 5 may defineconduits through which a cooling medium is adapted to circulate. Inother respects, 'the usual design of furnaces of this general type maybe followed and if desired, .the furnace arrangement may be manner.

' beneath.

of the general type disclosed in U. S. Patent No. 1,669,925, May 15,1928.

Preferably, the material to be treated is ground in suitable manner tobreak up the large pieces and then filtered to remove such quantities of5 moisture as may readily be disposed of in that Upon completion of thisoperation, the material may be fed into a hopper 6 fromwhich a screwconveyor 1, or equivalent, serves to transport the material so that itdrops down through 10 a conduit 8 which terminates interiorly of thefurnace F. From the conduit '8, the material falls uponthe uppermosthearth I and is rabbled inwardly by the teeth on the upper rabble arm 5so that said material passes downwardly through the opening la of theupper hearth l and thereby reaches the uppermost hearth 2. On the hearthlast named, the material is rabbled outwardly by the rabble arm whichcoacts therewith, the material eventually dropping from said hearth 2through the openings Za-at the edge thereof. In this manner, thematerial to be treated or incinerated is rabbled alternately inwardlyand outwardly across the superposed hearths of the Letters furnace, thematerial dropping through the inner opening of one hearth to 'the nextlower hearth and, after passage thereacross, dropping through theopenings at the periphery thereof so as to reach the periphery of thehearth there- The material, as it passes downwardly through the furnace,is first dried and then incinerated, the operation last noted occurringprincipally in the lower area of the furnace. It' will be understoodthat air is necessarily supplied .to the interior of the furnace for thepurpose of supporting combustion. In accordance with my invention, suchair is admitted into the furnace at or adjacent the top thereof andwithdrawn from said furnace in the region of the bottom thereof, theair, therefore, passing downwardly through the furnace in the samegeneral direction as is taken by the descending sewage material undertreatment.

The arrangement for causing the air to move downwardly through thefurnace'in the manner last described may be of any suitable character.To this end and as herein shown, a pipe or conduit 9 is so positionedthat it opens into the top of the furnace chamber F. A second pipe orconduit Ill opens into the bottom of said furnace chamber F and has anexhaust fan II, or equivalent device, connected thereto. When theexhaust fan I I is operated by a suitable motor, not 55 shown, theproducts of combustion are withdrawn from the bottom of .the furnace Fand caused to pass upwardlythrough said conduit Ill, and to bedischarged to the atmosphere, if desired. The products of combustionwhich are thus withdrawn from the furnace are replaced by air whichenters the top thereof through the conduit 9 which, preferably,communicates with the atmosphere as shown. Accordingly, in accordancewith the invention, a down-draft stream of air and gases is establishedwithin the furnace chamber and this is maintained during continuedoperation of the fan i I.

With the furnace in operation, combustion of the descending sewagematerial proceeds on one or more of the lower furnace hearths.Ordinarily, the gases evolved from the material under treatmentwouldrise through the furnace but, as stated above, the fan IIestablishes a downdraft stream of air. .Therefore, this air streamtogether-with the evolved gases necessarily passes through the abovenoted combustion zone and it is in this zone that the temperature is ata maximum interiorly of the furnace chamber.

'It results, therefore, due to the high tempera-- the gaseous materialwhich passes to the atmosphere through the conduit II is largely orsubstantially free from noxious gases which, if present, would causeannoyance to persons in the vicinity.

From the viewpoint of emciency and economy, itis desirable for-the hotgases passing from the furnace chamber tobe brought into heat-eichangingrelation with respect to the stream of air passing toward and into saidfurnace. This feature of the invention is illustrated on the drawingwhich shows a long section of the inlet pipe I as disposed interiorly ofa corresponding section of the outlet pipe II. By virtue of thisrelation, it is obvious that the gases passing to the top of the furnacechamber by way of the pipe l are pre-heated by the hot gases passingthrough the pipe II. In lieu of a heat-exchange arrangement of thecharacter shown, it is to be understood that any other suitable type ofarrangement may be utilized for accomplishing this purpose. I

As stated, an important feature of the invention relates to the passageor withdrawal of the hydrocarbon vapors through the hottest zone 'of thefurnace chamber, 1. e., the lower hearth or hearths on which occurs theprincipal combustion of the sewage material. Under such conditions, itwill be understood that the invention is not to be limited to thepassage of atmospheric air-from the pipe 9, or equivalent, into the topof the furnace chamber. As well, under some circumstances, this air maybe introduced into said furnace chamber nearer the middle thereofalthough it will be understood that it is advantageous for such air topass along a path of extendedlength while in contact with the sewagematerial so as to more effectively dry the same. As shown on thedrawing, one or more gas or oil nozzles l2, or equivalent, may beassociated with the furnace chamber so as to supply additional heatabove the lower hearthor hearths.

' The heat obtained from these sources may be utilized at any time whenthe furnace is to be placed in operation and, under some circumstances,it may be desirable to utilize such heat sources intermittently orcontinuously so as to obtain such number of heat units in the combustionzone as may be required to emciently 5 ,posed either interiorlyorexteriorly of the furnace chamber as desired.

As shown, the shaft 4 carries a lower gear I! with which meshes a secondgear it operated by a suitable motor i5 or other equivalent device. Withthe motor I5 operating, the sewage material descending through the pipe8 passes along a 20 circuitous path downward through the furnacechamber. Such materialis temporarily retained on each of the hearthswhile being advanced thereacross, the material, on each hearth i beingmoved toward the shaft 4 and, on each hearth 2, 25 being moved outwardlyfrom said shaft 4.

' The air which is admitted into the furnace chamber through the pipe 0,or equivalent, likewise passes along a circuitous descending path whilecontacting with. the descending sewage material. It will be understoodthat such air passes inwardly toward the shaft 4 above the hearths l andoutwardly from said shaft above the hearths 2, the air passingdownwardly through the inner passages la of the respective hearths i andthe outer passages 2a. of the respective hearths 2. .As a result, thesewage material is dried in an eifective manner in the upper furnaceregions and as such material descends through the furnace, it becomesprogressively 4o dryer. On one or more of the lower hearths, combustionof the dried material is completed and, under proper operatingconditions, it results that such material becomes principally an ash bythe time it reaches the lower hearth from which it maybe removed througha suitable conduit it or the like.

Under some circumstances, it may be desirable to treat the moistmaterial on the upper hearth or hearths with one stream of air, pre-.heated or otherwise, and to treat the dry and burning material on thelower hearths with another stream of air. Due to the moist condition ofthe material, the first named stream of air remains substantiallyodorless and hence may 65 be passed to the atmosphere without objection.The second named stream of air becomes odorladen, however, and it isthis air stream which is passed down-draftthrough the combustion zone orotherwise treated to deodorize the same, i. e., effect the removal ofnoxious odors. By proceeding in the manner just described, it is obviousthat there is a substantial decrease in the volume of air which issubjected to heat treatment. This, of course, is decidedly advantageous.In view of all the foregoing, it becomes obvious that my novel processis especially advantageous, useful and efllcient because dependingprincipally or entirely upon the heat generated by combustion of thesewage material for the elimina- 7 tion of noxious odors from thehydrocarbon gases. The expense of the complete operation issubstantially decreased while, at the same time, the amount of equipmentis decreased in comparison with the equipment required by prior art 76arrangements for accomplishing the same end.

While the invention has been described with respect to certainparticular preferred examples which give satisfactory results, 'it willbe understood by those skilled in the art after understanding theinvention, that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention and itis intendedtherefore in the appended claims to cover all such changes andmodifications.

What is claimed as new and desired to be securedby Letters Patent is:

1. The process of treating sewage or similar material, which comprisespassing said material downwardly through a plurality of superposed zoneswhile first drying and then burning the same, temporarily retaining saidmaterial in each of a plurality of said zones, moving said materialhorizontally through each of said zones by the application of a seriesof successive rabbling impulses thereto, passing a stream of airdownwardly through said zones along the path of travel of the materialat each'of said zones successively, whereby the gaseous products ofcombustion produced with said air are made substantially free of noxiousodors in passing through the lower of said zones where burning occurs,

discharging said products of combustion from the lowermost zone bysuction, and subjecting said air prior to its introduction to-theuppermost zone to heat interchanging relationship with the exit gasesfrom said lowermost zone.

2. The process of incinerating sewage material to form an ash andevolved gases free of noxious odor, which comprises first treating thematerial to remove therefrom a substantial portion of the moisturecontent thereof, then passing said material downwardly through aplurality of superposed zones while first drying and then burning thesame, temporarily retaining said material in horizontal layers at eachof said zones while periodically agitating and advancing it through eachzone and gradually from zone to zone, said drying being effected byintroducing a stream of preheated air into contact with the material atthe zones of drying, and passing said stream of air downwardly from saiddrying zones along the path of travel of the material through the zonesof burning, whereby the gases evolved from the drying material and thegaseousprodnets of combustion are heated at the zones of burning, to ahigh temperature for the substantial elimination of noxious odorstherefrom.

a HENRY-J. HARTLEY.

